Hi,
I've tried having a look on google to see if anyone has tried this before but havent had any success so... I'm currently using a TPA3116d2 2.1 amp but im missing the sound of my old Class A amp but the only issue is the majority of older amps dont have any subwoofer output like the TPA. Would it be possible to use a low pass filter combined with a Y adapter to take the L and R signal from the amp combine them and then send that LPF signal to the passive subwoofer. Probably not the best explanation so enjoy some paint.
Thanks for the help